New tires are expensive. As a result, replacing and maintaining tires can be an economic burden for those who manage a large fleet vehicles or otherwise place excessive wear on their tires. Replacing tires can also be a burden for those of modest means.
As a result, it is becoming increasingly important to repair damaged tires rather than replace them with new tires. Repairing a damaged tire is usually very simple and inexpensive, especially repairing simple holes or objects that become embedded in the treaded portion of the tire.
Diagnosis is the first step in repairing a damaged tire. It is necessary to ascertain if any foreign objects are embedded in the tread portion of the tire or if any cracks, fissures, or holes exist therein. The prior art has typically relied upon visual inspection in order to make this determination. If such defects are found to exist, the tire can be repaired. If the defect is not found, the tire must be replaced.
There are several techniques for inspecting a tire. One such technique is visual inspection, which tends to be slow and time consuming. More importantly, however, this method for searching for defects is, at best, unreliable. With this method, a tire is rotated on a mounting stand, and an inspector visually observes the tread portion of the tire as it passes beneath his gaze. The difficulties is that some defects are so minute that they escape the detection of even a trained, experienced observer. Even these defects can weaken the tire and become a hazard to vehicles operating at high rates of speed.
In an attempt to solve some of the problems inherent in visual inspection, other types of testing techniques have been devised. One such method involves over inflating a tire and either immersing the tire in a fluid or applying a fluid to the outer surface thereof. A leak of air through an orifice or fissure can be detected visually more readily by the observation of a bubbling effect, which will occur at the location of the defect. This method, however, will not detect defects other than well defined holes that pass all the way through the treaded portion of a tire.
Another inspection technique uses a wand that has an electrode and a high voltage power supply. An inspector passes the wand over the surface of the tire and watches for any arcing that occurs between the electrode and nails embedded in the tire or holes that expose the steel belt from the tire. The difficulty with such wands, is that the inspector may not pass the electrode over the entire surface of the tire's tread portion and thus fail to detect some defects. Another shortcoming is that such a wand will not detect a simple hole or puncture mark if there is not a metal object or belt embedded in the tire.
More complex systems for detecting tire defects also exist. In one such system, the tread portion of a tire is sandwiched between a pair of electrodes across which a high voltage electrical potential is generated. With this system, if objects such as nails are embedded in the tread portion of the tire or if defects such as orifices or fissures exist, the voltage applied across the electrodes will cause arcing at the point of foreign object or defect. Such a device typically rotates the tire such that the tread portion passes between the electrodes. Additionally, such an apparatus typically includes an electronics package whereby as a defect is detected by arcing across the electrodes, rotation of the tire is stopped, and an alarm is actuated. Pinpointing the location of the defect is, thereby, facilitated.
Such advanced machines are typically complex, large, and expensive. They are appropriate for high volume retreading operations that inspect and retread a large number of tires. Additionally, these advanced machines are typically too expensive and too large for smaller garages and tire shops that do not inspect and repair tires in mass.
Therefore, there is a need for an improved tire defect tester. Such an improved tire defect tester would be inexpensive and simple to use. Such a tire defect tester would also ensure that the entire treaded portion of the tire is thoroughly inspected.